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International Journal of Environmental... Nov 2021Urban population density distribution contributes towards a deeper understanding of peoples' activities patterns and urban vibrancy. The associations between the...
Urban population density distribution contributes towards a deeper understanding of peoples' activities patterns and urban vibrancy. The associations between the distribution of urban population density and land use are crucial to improve urban spatial structure. Despite numerous studies on population density distribution and land use, the significance of spatial dependence has attained less attention. Based on the Baidu heat map data and points of interests data in the main urban zone of Guangzhou, China, the current paper first investigated the spatial evolution and temporal distribution characteristics of urban population density and examined the spatial spillover influence of land use on it through spatial correlation analysis methods and the spatial Durbin model. The results show that the urban population density distribution is characterized by aggregation in general and varies on weekends and weekdays. The changes in population density within a day present a trend of "rapid growth-gentle decline-rapid growth-rapid decline". Furthermore, the spatial spillover effects of land use exist and play the same important roles in population density distribution as the direct effects. Additionally, different types of land use show diverse direct effects and spatial spillover effects at various times. These findings suggest that balancing the population density distribution should consider the indirect effect from neighboring areas, which hopefully provide implications for urban planners and policy makers in utilizing the rational allocation of public resources and regarding optimization of urban spatial structure.
Topics: China; Cities; Humans; Population Density; Spatial Analysis; Urban Population; Urbanization
PubMed: 34831916
DOI: 10.3390/ijerph182212160 -
PLoS Computational Biology Apr 2022Population size has long been considered an important driver of cultural diversity and complexity. Results from population genetics, however, demonstrate that in...
Population size has long been considered an important driver of cultural diversity and complexity. Results from population genetics, however, demonstrate that in populations with complex demographic structure or mode of inheritance, it is not the census population size, N, but the effective size of a population, Ne, that determines important evolutionary parameters. Here, we examine the concept of effective population size for traits that evolve culturally, through processes of innovation and social learning. We use mathematical and computational modeling approaches to investigate how cultural Ne and levels of diversity depend on (1) the way traits are learned, (2) population connectedness, and (3) social network structure. We show that one-to-many and frequency-dependent transmission can temporally or permanently lower effective population size compared to census numbers. We caution that migration and cultural exchange can have counter-intuitive effects on Ne. Network density in random networks leaves Ne unchanged, scale-free networks tend to decrease and small-world networks tend to increase Ne compared to census numbers. For one-to-many transmission and different network structures, larger effective sizes are closely associated with higher cultural diversity. For connectedness, however, even small amounts of migration and cultural exchange result in high diversity independently of Ne. Extending previous work, our results highlight the importance of carefully defining effective population size for cultural systems and show that inferring Ne requires detailed knowledge about underlying cultural and demographic processes.
Topics: Biological Evolution; Computer Simulation; Genetics, Population; Phenotype; Population Density
PubMed: 35395004
DOI: 10.1371/journal.pcbi.1009430 -
Environmental Science and Pollution... Aug 2021Currently, 2019-nCoV has spread to most countries of the world. Understanding the environmental factors that affect the spread of the disease COVID-19 infection is...
Currently, 2019-nCoV has spread to most countries of the world. Understanding the environmental factors that affect the spread of the disease COVID-19 infection is critical to stop the spread of the disease. The purpose of this study is to investigate whether population density is associated with the infection rate of the COVID-19. We collected data from official webpages of cities in China and in the USA. The data were organized on Excel spreadsheets for statistical analyses. We calculated the morbidity and population density of cities and regions in these two countries. We then examined the relationship between morbidity and other factors. Our analysis indicated that the population density in cities in Hubei province where the COVID-19 was severe was associated with a higher percentage of morbidity, with an r value of 0.62. Similarly, in the USA, the density of 51 states and territories is also associated with morbidity from COVID-19 with an r value of 0.55. In contrast, as a control group, there is no association between the morbidity and population density in 33 other regions of China, where the COVID-19 epidemic is well under control. Interestingly, our study also indicated that these associations were not influenced by the first case of COVID-19. The rate of morbidity and the number of days from the first case in the USA have no association, with an r value of - 0.1288. Population density is positively associated with the percentage of patients with COVID-19 infection in the population. Our data support the importance of such as social distancing and travel restriction in the prevention of COVID-19 spread.
Topics: COVID-19; China; Humans; Pandemics; Physical Distancing; Population Density; SARS-CoV-2
PubMed: 33442802
DOI: 10.1007/s11356-021-12364-4 -
Scientific Reports Apr 2022Dispersal reflects the trade-offs between the cost of a change in habitat and the fitness benefits conferred by that change. Many factors trigger the dispersal of...
Dispersal reflects the trade-offs between the cost of a change in habitat and the fitness benefits conferred by that change. Many factors trigger the dispersal of animals, but in field studies they are typically not controllable; consequently, they are mostly studied in the laboratory, where their single and interactive effects on dispersal can be investigated. We tested whether three fundamental factors, population density as well as bottom-up and top-down control, influence the emigration of the nematode Caenorhabditis elegans. Nematode movement was observed in experiments conducted in two-chamber arenas in which these factors were manipulated. The results showed that both decreasing food availability and increasing population density had a positive influence on nematode dispersal. The presence of the predatory flatworm Polycelis tenuis did not consistently affect dispersal but worked as an amplifier when linked with population density with respect to certain food-supply levels. Our study indicates that nematode dispersal on small scales is non-random; rather, the worms' ability to perceive environmental information leads to a context-dependent decision by individuals to leave or stay in a patch. The further use of nematodes to gain insights into both the triggers that initiate dispersal, and the traits of dispersing individuals will improve the modeling of animal behavior in changing and spatial heterogenous landscapes.
Topics: Animals; Ecosystem; Population Density
PubMed: 35368038
DOI: 10.1038/s41598-022-09631-w -
Scientific Reports Apr 2022The time period between 560 and 360 ka (MIS14 to MIS11) was critical for the evolution of the Neanderthal lineage and the appearance of Levallois technology in Europe....
The time period between 560 and 360 ka (MIS14 to MIS11) was critical for the evolution of the Neanderthal lineage and the appearance of Levallois technology in Europe. The shifts in the distribution of the human populations, driven by cyclical climate changes, are generally accepted to have played major roles in both processes. We used a dataset of palaeoclimate maps and a species distribution model to reconstruct the changes in the area of Western Europe with suitable environmental conditions for humans during 11 time intervals of the MIS14 to MIS 11 period. Eventually, the maximum sustainable human population within the suitable area during each time interval was estimated by extrapolating the relationship observed between recent hunter-gatherer population density and net primary productivity and applying it to the past. Contrary to common assumptions, our results showed the three Mediterranean Peninsulas were not the only region suitable for humans during the glacial periods. The estimated total sustainable population of Western Europe from MIS14 to MIS11 oscillated between 13,000 and 25,000 individuals. These results offer a new theoretical scenario to develop models and hypotheses to explain cultural and biological evolution during the Middle Pleistocene in Western Europe.
Topics: Animals; Climate Change; Europe; Hominidae; Humans; Neanderthals; Population Density
PubMed: 35484382
DOI: 10.1038/s41598-022-10642-w -
Scientific Reports Jun 2022Thriving under high population density is considered a major feature of urban exploiter species. Nevertheless, population density appears to be a surprisingly overlooked...
Thriving under high population density is considered a major feature of urban exploiter species. Nevertheless, population density appears to be a surprisingly overlooked factor in urban ecology studies. High population numbers observed in urban species might promote pathogen transmission and negatively affect health or condition, thus requiring investments in immunocompetence. The feral pigeon Columba livia domestica is an example of a successful city-dweller, found in great abundance in large cities across the globe. We investigated the effects of population density on induced immune response (phytohaemagglutinin skin test) and body condition (blood haemoglobin concentration and size-corrected body mass) in 120 feral pigeons, captured along population density gradient in Łódź (central Poland). We found that stronger immune response was associated with higher population density, but was not related to physiological condition and physiological stress (heterophil/lymphocyte ratio). Moreover, condition indices were not associated with population density. However, since pigeon population density was highly correlated with the level of habitat urbanization, we cannot exclude that any density-dependent effects may be mediated by habitat variation. Our results indicate that urban environment, via population density, might exert different selective pressures on immunocompetence and body condition in this successful urban exploiter.
Topics: Adaptation, Physiological; Animals; Columbidae; Immunity; Population Density; Urbanization
PubMed: 35650222
DOI: 10.1038/s41598-022-12910-1 -
The Science of the Total Environment Jun 2024Accurate prediction of fluctuations of wildlife local number of individuals is crucial for effective population management to minimise human-wildlife conflicts. Climate,...
Accurate prediction of fluctuations of wildlife local number of individuals is crucial for effective population management to minimise human-wildlife conflicts. Climate, habitat, food availability, and density dependence are among the main factors influencing mammalian population dynamics. In southern Europe, precipitation and temperature, particularly during summer have been suggested as key factors affecting wild boar (Sus scrofa L.). However, there is uncertainty regarding the role of these factors and the mechanisms driving population fluctuations. This study utilized long-term data of wild boar populations from 14 study sites collected for 23 years in Catalonia, Spain, to analyse the factors that drive population density and growth rate. Generalized Additive Mixed Models (GAMM) explained respectively, 94 % and 65 % of the density and growth rate variability. Spring precipitation in both current and previous year, female weight, and forest cover (particularly above 60 %) were directly associated with higher wild boar densities and population growth rates. The interaction between crop cover and total annual precipitation also played a significant role in determining population density. Higher densities were linked to lower population growth in the following year, likely due to a density-dependent process. These results suggest that the expected decrease in rainfall linked with global warming may limit the availability of natural resources and potentially slow wild boar population growth. Nevertheless, wild boar can exploit alternative anthropogenic food sources, potentially leading to an increase of human-wildlife conflicts. Therefore, incorporating management policies aimed at restricting wild boar access to human food sources is key for controlling their reproductive output. Additionally, landscape management strategies targeted at diminishing refuge and resource availability in regions experiencing high wild boar impact are essential for contributing to sustainable coexistence between wild boars and human populations.
Topics: Animals; Sus scrofa; Spain; Population Density; Population Growth; Ecosystem; Population Dynamics; Animals, Wild; Conservation of Natural Resources
PubMed: 38697537
DOI: 10.1016/j.scitotenv.2024.172739 -
Philosophical Transactions of the Royal... Jan 2021Radiocarbon summed probability distribution (SPD) methods promise to illuminate the role of demography in shaping prehistoric social processes, but theories linking...
Radiocarbon summed probability distribution (SPD) methods promise to illuminate the role of demography in shaping prehistoric social processes, but theories linking population indices to social organization are still uncommon. Here, we develop Power Theory, a formal model of political centralization that casts population density and size as key variables modulating the interactive capacity of political agents to construct power over others. To evaluate this argument, we generated an SPD from 755 radiocarbon dates for 10 000-1000 BP from Central, North Central and North Coast Peru, a period when Peruvian political form developed from 'quasi-egalitarianism' to state levels of political centralization. These data are congruent with theoretical expectations of the model but also point to an artefactual distortion previously unremarked in SPD research. This article is part of the theme issue 'Cross-disciplinary approaches to prehistoric demography'.
Topics: Archaeology; Demography; Humans; Peru; Politics; Population Density
PubMed: 33250024
DOI: 10.1098/rstb.2019.0725 -
International Journal of Environmental... Aug 2021Despite numerous studies on multiple socio-economic factors influencing urban PM pollution in China, only a few comparable studies have focused on developed countries....
Despite numerous studies on multiple socio-economic factors influencing urban PM pollution in China, only a few comparable studies have focused on developed countries. We analyzed the impact of three major socio-economic factors (i.e., income per capita, population density, and population size of a city) on PM concentrations for 254 cities from six developed countries. We used the Stochastic Impacts by Regression on Population, Affluence and Technology (STIRPAT) model with three separate data sets covering the period of 2001 to 2013. Each data set of 254 cities were further categorized into five subgroups of cities ranked by variable levels of income, density, and population. The results from the multivariate panel regression revealed a wide variation of coefficients. The most consistent results came from the six income coefficients, all of which met the statistical test of significance. All income coefficients except one carried negative signs, supporting the applicability of the environmental Kuznet curve. In contrast, the five density coefficients produced statistically significant positive signs, supporting the results from previous studies. However, we discovered an interesting U-shaped distribution of density coefficients across the six subgroups of cities, which may be unique to developed countries with urban pollution. The results from the population coefficients were not conclusive, which is similar to the results of previous studies. Implications from the results of this study for urban and national policy makers are discussed.
Topics: Air Pollutants; Air Pollution; China; Cities; Developed Countries; Environmental Monitoring; Particulate Matter; Population Density
PubMed: 34501609
DOI: 10.3390/ijerph18179019 -
Frontiers in Public Health 2021The impact of social participation (SP) on the health of the elderly has been widely recognized, and urban-rural differences in social participation have attracted...
The Influence of Interpersonal Behaviors and Population Density on Grip Strength of Elderly People: An Analysis of the Direct vs. Indirect Effects via Social Participation.
The impact of social participation (SP) on the health of the elderly has been widely recognized, and urban-rural differences in social participation have attracted attention. However, few studies discussed the impact of social participation on specific health indicators and the further subdivision of urban-rural differences. This research aims to use the dimensions of interpersonal behaviors and population density rather than simple urban-rural distinctions to justify community differences and compare these differences' direct and indirect effects on grip strength. This study used 15,871 respondents aged over 50 years from the China Health and Retirement Longitudinal Study (CHARLS). An SEM (Structural Equation Modeling) analysis was used to explore the joint effect of interpersonal behavior and population density on social participation and the consequent impact on changes in grip strength and compare the differences among different genders, ages, wealth levels, and family relationships. The results indicated that community differences characterized by interpersonal behavior and population density have direct effects on grip strength and indirect effects on it through social participation. The conclusion is that the frequency of social activities, such as mah-jong and dancing in the Metropolitan Fringe and county-level cities is higher than that in Metropolitan centers. The high frequency of these activities has a positive and indirect impact on grip strength, and community differences have a more significant impact on women's social participation than men. However, the direct effect of community differences as defined by interpersonal communication and population density on grip strength is greater than the indirect effect of other factors through social participation.
Topics: Aged; China; Female; Hand Strength; Humans; Longitudinal Studies; Male; Population Density; Social Participation
PubMed: 34957015
DOI: 10.3389/fpubh.2021.755695